Faculty Bibliography

Background: Unfavorable outcomes observed with stepwise linear ablation of non-paroxysmal AF (NPAF) in large clinical trials utilizing ablation catheters without contact-force sensing (CFS) may be attributable to pro-arrhythmic effects of incomplete ablation lines. The optimal ablation strategy for catheter ablation of NPAF using a contact force sensing radiofrequency (RF) ablation catheter remains unclear. Objective: To compare catheter ablation outcomes of stepwise linear ablation to left atrial (LA) posterior wall isolation in patients undergoing NPAF ablation using a CFS RF ablation catheter. Methods: We performed pulmonary vein antral isolation (PVAI) followed by isolation of the LA posterior wall in 80 consecutive patients undergoing first-time NPAF ablation between November 2015 and March 2016 (Group 1) and compared clinical outcomes to those of 112 consecutive patients who underwent PVAI followed by step-wise linear ablation for NPAF between May 2014 and November 2015 (Group 2). All ablation procedures were performed using the Carto 3 mapping system and SmartTouch RF ablation catheter (Biosense Webster, Inc.). Arrhythmia recurrence was assessed using 2-week event monitors at 3-month intervals. Arrhythmia-free survival at 12 months was estimated using the Kaplan-Meier method. Results: Baseline characteristics of Group 1 and Group 2 were similar. At 12 months follow-up, arrhythmia-free survival was significantly greater in Group 1 patients compared with Group 2 (81.9% vs. 67.5%, respectively; p=0.0318). There was no significant difference in survival free from AF between group 1 and group 2 (89% vs. 84.1%, respectively; p=0.3431), however group 1 patients developed significantly fewer post-ablation atrial tachycardias (AT) than group 2 patients (8.1% vs 30.1%, respectively; p<0.001). Conclusion: Among patients undergoing NPAF ablation using a contact force sensing RF ablation catheter, LA posterior wall isolation resulted in fewer recurrent atrial arrhythmias than a stepwise linear approach. The reduction in recurrent atrial arrhythmias is driven primarily by a reduction in recurrent AT

BACKGROUND: Patients on rivaroxaban have variable INRs, but it is uncertain if INR impacts procedural heparin requirement during left atrial ablation. We sought to examine the determinants of heparin dosing in this patient population. METHODS: We reviewed consecutive patients who received rivaroxaban within 24 hours of left atrial ablation and compared them to patients on uninterrupted warfarin. The determinants of heparin requirement were evaluated using regression analysis. We then tested a weight based heparin dose prospectively in rivaroxaban patients. RESULTS: There were 258 patients on rivaroxaban and 213 on warfarin. The mean INR was 1.4 in the rivaroxaban group and 2.3 in the warfarin group (p<0.01). To achieve an activated clotting time (ACT) >350 seconds, rivaroxaban patients required significantly more heparin (166.9 vs. 78.3 units/kg, p<0.001). In the rivaroxaban group, body weight was the strongest predictor of heparin dose (r = 0.52) while INR was weakly correlated (r = -0.21). In the prospective group, 25 patients were given an initial heparin dose of 120 units/kg with 22/25 (88%) achieving an ACT >300 seconds. There were 7 and 3 cases of pericardial effusion in rivaroxaban and warfarin patients, respectively (p = 0.41). The average volume drained in the rivaroxaban group was elevated (988.6 vs. 275.0 milliliters, (p = 0.21). CONCLUSIONS: Body weight is the strongest predictor of procedural heparin requirement during left atrial ablation in patients on uninterrupted rivaroxaban, even in those with an elevated INR. A heparin dose of 120 units/kg achieves an ACT >300 seconds in the majority of patients. In cases of pericardial effusion, bleeding may be prolonged

OBJECTIVES/OBJECTIVE:The aim of this study was to categorize arrhythmia mechanisms and to summarize ablation strategies in patients with persistent pulmonary vein isolation (PVI) at the time of redo procedures. BACKGROUND:Persistent PVI is more frequently seen in patients undergoing redo procedures for recurrent atrial arrhythmias after catheter ablation for atrial fibrillation (AF). METHODS:Consecutive patients who underwent their first AF ablation procedures at Brigham and Women's Hospital were screened and included if they had persistent isolation of all pulmonary veins at the time of redo procedures. RESULTS:Of 300 consecutive patients undergoing first AF ablation procedures, redo procedures were performed in 63 (21%), and 26 patients (9%) had persistent PVI. Of those, 11 had recurred with AF and 15 with organized atrial tachycardia (AT). During the index procedure, linear ablation was performed in 46% of patients with recurrent AF and 93% with recurrent organized AT (p = 0.020). At the time of last follow-up, 2 of 10 patients (20%) in the AF group and 10 of 15 patients (67%) in AT group were in sinus rhythm, without class I or III antiarrhythmic drugs (p = 0.022). CONCLUSIONS:Patients with recurrence of atrial arrhythmia despite persistent PVI frequently present with organized AT. Linear ablation during the index procedure is associated with recurrence of organized AT. Recurrence rates after redo procedures were higher if patients had recurrent AF after the index procedure, and these patients often presented with AF again. Patients with recurrent AF despite persistent PVI may represent a population with lower success rates of catheter ablation.

BACKGROUND:Long-term outcomes after ventricular tachycardia (VT) ablation are sparsely described. OBJECTIVES:The purpose of this study was to describe long-term prognosis after VT ablation in patients with no structural heart disease (no SHD), ischemic cardiomyopathy (ICM), and nonischemic cardiomyopathy (NICM). METHODS:Consecutive patients (N = 695: no SHD, 98; ICM, 358; NICM, 239) ablated for sustained VT were followed for a median of 6 years. Acute procedural parameters (complete success [noninducibility of any VT]) and outcomes after multiple procedures were reported. RESULTS:Compared with patients with no SHD or NICM, patients with ICM were the oldest, were more likely to be men, lowest left ventricular ejection fraction, highest drug failures, VT storms, and number of inducible VTs. Complete procedure success was highest in patients with no SHD than in patients with ICM and those with NICM (79%, 56%, 60%, respectively; P < .001). At 6 years, ventricular arrhythmia (VA)-free survival was highest in patients with no SHD (77%) than in patients with ICM (54%) and those with NICM (38%) (P < .001), and overall survival was lowest in patients with ICM (48%), followed by patients with NICM (74%) and patients with no SHD (100%) (P < .001). Age, left ventricular ejection fraction, presence of SHD, acute procedural success (noninducibility of any VT), major complications, need for nonradiofrequency ablation modalities, and VA recurrence were independently associated with all-cause mortality. CONCLUSION:Long-term follow-up after VT ablation shows excellent prognosis in the absence of SHD, highest VA recurrence, and transplantation in patients with NICM and highest mortality in patients with ICM. The extremely low mortality for those without SHD suggests that VT in this population is rarely an initial presentation of a myopathic process.

Introduction: Use of contact force sensing ablation catheters and automated lesion annotation software has improved reliability of radiofrequency (RF) ablation lesion creation. Predictors of poor lesion creation despite adequate contact force and power are not well understood. Methods: Discrete biatrial lesions were created in 9 in vivo porcine hearts with a power of 30 W using a contact force sensing, 3.5 mm irrigated ablation catheter (SmartTouch, Biosense Webster). Lesion location was tagged using a 3D mapping system (Carto 3, Biosense Webster). Lesion duration was guided by Force Time Integral = 400 g*s using an automated lesion annotation system (VisiTag, Biosense Webster). Transmurality of ablation lesions and lesion dimensions were assessed grossly after TTC staining. The length and width of each lesion was measured on the endocardium and epicardium, and the smallest dimension was designated the minimum transmural diameter (MTD). Nontransmural lesions and lesions that could not be found were assigned a MTD of 0 mm. Results: Thirty-five discrete lesions created in non-trabeculated atrial tissue were correlated to lesions on the 3D map. There were 21 lesions with MTD>5mm(5.7+/-0.4mm, Group1) and 14lesions with MTD < 5 mm (4.5 +/- 0.3 mm, Group 2). Group 1 and group 2 lesions had similar FTI (428.5 +/-18.9 g*s vs. 426.8 +/-15.3 g*s, p = 0.78), Force Power Time Integral (4.5 +/- 0.3 cm vs. 4.4 +/- 0.5 cm, p=0.4), and RF duration (25.7 +/- 8.9 s vs. 25.2 +/- 5.7 s, p=0.85). While there was no difference in total impedance decrease between group 1 and group 2 (29.6 +/-15.2Q vs. 25.7 +/-10.0 Q, p=0.4), Group 1 lesions had a greater impedance decrease at 15s (33.4+/-13.9 O. vs. 24.0+/-9.0 O., p=0.03). In addition, group 1 lesions achieved a higher average temperature (43.0 +/- 5.3 degreeC vs. 39.3.7 +/- 5.2degreeC, p<0.05) and were created with a smaller catheter-tissue angle (54.1 +/- 21.1degree vs. 71.4 +/- 22.8degree, p=0.03). Conclusions: Automated lesion annotation technology based solely on contact force, RF duration, and RF power does not reliably predict lesion size in smooth, atrial tissue. Consideration of impedance decrease at 15s, average electrode temperature, and catheter-tissue angle may improve predictive accuracy of automated lesion annotation

Introduction: Large clinical trials have recently demonstrated stepwise linear ablation for non-paroxysmal atrial fibrillation (NPAF) to be inferior to pulmonary vein isolation alone. It is unknown whether the unfavorable outcomes observed in these trials can be attributed to the pro-arrhythmic effects of incomplete ablation lines. We hypothesized that improved lesion quality related to use of contact-force sensing (CFS) ablation catheters would improve procedural outcomes. Methods: We prospectively analyzed procedural outcomes of 74 consecutive patients with NPAF undergoing first-time radiofrequency catheter ablation with a CFS catheter (Smart Touch, Biosense Webster) using a step-wise approach (Group 1). The clinical outcomes of these patients were compared with 74 consecutive patients with NPAF who underwent catheter ablation between September 2013 and June 2014 with a non-contact force sense radiofrequency ablation catheter (Group 2) at a single tertiary care medical center. Arrhythmia recurrence was assessed using 2-week event monitors at 3-month intervals following index ablation. Results: Baseline characteristics of Group 1 and Group 2 were similar, although in Group 1 there was a greater prevalence of patients with persistent NPAF lasting for 6-months or longer prior to initial ablation (43% vs 21%, p=0.071). The recurrence rate at 1 year as estimated by the Kaplan-Meier method was not significantly different between Group 1 and Group 2 (25.7% vs 29.7%, p=0.582). The presenting recurrent arrhythmia was most frequently atrial tachycardia (AT) in both groups (Group 1: n=19, AT 68.4% and AF 31.6% vs Group 2: n=22, AT 59.1% and AF 40.9%). A similar proportion of patients in both groups underwent repeat ablation (Group 1: 17.6% vs Group 2: 13.5%, p=0.496). Conclusions: Utilization of a CFS ablation catheter was not associated with improved clinical outcomes for stepwise catheter ablation for NPAF. The optimal strategy for NPAF ablation using a contact-force sensing catheter remains undefined

Introduction: LA ablation for persistent AF that achieves organization to atrial tachycardia (AT) or sinus rhythm (SR) predicts greater long term ablation success. However, extensive LA ablation increases the risks of recurrent AT, adverse atrial remodeling and procedural complications. Preclinical and observational studies suggest that right atrial ablation may reduce AF risk. We hypothesized that CTI ablation may reduce the extent of LA ablation required to achieve organization of persistent AF. Methods: Persistent AF patients (n=107) were randomized to two arms (CTI-first or CTI-last) in a single center, prospective, single blind study. Excluding the CTI ablation, stepwise linear LA ablation was performed in a prespecified order. The primary endpoint was the percentage of patients who organized to AT or SR. The secondary endpoint was number of steps to organization. Results: CTI ablation first versus last during AF ablation did not significantly alter the percentage of patients who organized (Table). Among those who organized, the number of steps to organization did not differ between the two arms. No significant differences were found when patients were stratified by LA size or AF duration. Conclusions: CTI ablation does not alter the extent of LA ablation needed to achieve organization of AF. The utility of right atrial ablation for persistent AF ablation remains unclear. (Table presented)

Introduction: Transcatheter aortic valve replacement (TAVR) is becoming a widely accepted alternative treatment for patients with symptomatic aortic stenosis who are at high risk for surgical aortic valve replacement. A common complication of the procedure is the development of conduction defects requiring permanent pacemaker (PPM) implantation. It has been noted that in some patients, the conduction block is not permanent. Determine the incidence and predictors of resuming intrinsic conduction in patients that receive PPM implantation after TAVR. Methods: A retrospective chart review of patients undergoing TAVR at New York University Langone Medical Center was undertaken. Extracted data included patient demographics, pre-TAVR electrocardiogram, procedural, echocardiographic, catheterization, and device interrogation data. Evaluation of device interrogations done at one month follow-up or earlier to look for resumption of intrinsic conduction. Results: There were a total number of 451 patients who were status-post TAVR in our registry at NYU. Of the 451, 45 patients received a permanent pacemaker placement for complete heart block; 9.9% 45/451. The majority of patients were implanted within 48hrs post TAVR. Device follow-up information at 1 month or earlier was available for 33 of the 45 patients who received PPM. 5 patients who were recently implanted are still pending follow-up. 3 patients expired after implantation and 4 were lost to follow-up. Of the 33 patients, 14 (42%) patients had resumption of AV nodal conduction at 1 month follow-up. 19 patients (57%) remained dependent. Conclusions: 42% of patients who received a permanent pacemaker for complete heart block after TAVR had resumption of conduction. This suggests that many patients may not require long term PPM post TAVR. Patients that remained dependent had a higher incidence of preexisting RBBB and LAFB, however a lack thereof does not preclude an increased risk. These data suggest that waiting longer than 48 hours for resumption of AV nodal conduction would avoid unnecessary implantation in patients who develop complete heart block post TAVR

OBJECTIVES/OBJECTIVE:This study sought to assess the incidence, operator demographics, clinical characteristics, procedural factors, and prognosis of esophageal perforation and fistula after atrial fibrillation ablation. BACKGROUND:Esophageal injury is a feared complication of atrial fibrillation ablation. METHODS:An Internet-based global survey soliciting anonymous information regarding esophageal perforation and fistula was emailed to 3,080 physicians. Detailed information regarding physician, patient, and procedural characteristics related to esophageal perforation with or without fistula was collected. RESULTS:; p = 0.03), and lower left ventricular ejection fraction (55.1 ± 9.1% vs. 61.7 ± 5.4%; p = 0.04). Among analyzed patients, atrial-esophageal fistula was seen in 72%, pericardial-esophageal fistula in 14%, and esophageal perforation without fistula in 14%. Mortality was 79% with atrial-esophageal fistula and 13% in esophageal perforation without atrial-esophageal fistula. CONCLUSIONS:Esophageal perforation is rare but continues to occur with multiple catheter types despite esophageal monitoring during ablation. The prognosis of esophageal perforation is substantially improved if diagnosed and treated before development of atrial-esophageal fistula. An early surgical approach to esophageal perforation should be strongly considered regardless of evidence of fistula.